Mild traumatic brain injury (mTBI), commonly referred to as a concussion, is a type of traumatic brain injury (TBI) caused by a fall, a blow to the head, or another injury that jars or shakes the brain inside the skull. In some instances, there may be no lasting symptoms or ill effects because the brain is protected by the skull and cushioned by the cerebrospinal fluid to absorb impacts. However, the force of an impact may be beyond the ability of the skull and cerebrospinal fluid to fully protect the brain, which can lead to mTBI.
Diagnosing mTBI in its earliest and least problematic stages is critical to effective intervention, which will improve clinical outcomes and reduce costly long term care. In its Science and Technology (S&T) Path Ahead report of Oct. 3, 2012, the Army proclaims “early detection of TBI” as one of its top challenges, with planned investments of $5 million for FY14 and $40 million for FY14-18 to address the challenge. Further, many sporting leagues, from grade school and college athletics to professional leagues, have a need for thorough implementation of sideline concussion protocols that easily and reliably screen for mTBI and thus adequately protect athletes from risk of further injury. Therefore, it would be helpful, especially for entities such as the military and various sports leagues, to have a mTBI screening system that can easily and reliably screen for mTBI immediately following a traumatic exposure.
Common symptoms of mTBI include psychomotor slowing, poor concentration, and decrease in attention retrieval ability, leading to increased variability of performance and overall executive dysfunction. Executive dysfunction further causes poor regulation and control of cognitive processes, including working memory, logical reasoning, and problem solving. Problematically, the onset of mTBI is very subtle, making early identification of mTBI difficult. Indeed, one of the greatest challenges in diagnosing mTBI is that most persons with mTBI do not exhibit clearly discernible symptoms immediately following the traumatic exposure. Symptoms may not appear for days, weeks, or even months and when they do appear, they are often nonspecific. Further, persons with mTBI are more susceptible to additional, and potentially more severe, brain damage. Therefore, the ability to reliably identify mTBI early on in its course is especially important.
The military in particular has a great need to screen for mTBI among its troops. Various mTBI symptoms, including headaches, irritability, memory impairments, dulled reaction time, and insomnia, lead to decrease in performance that is particularly dangerous for troops involved in combat or in close proximity to a hostile area. Traditional approaches to assessing mTBI, such as detailed neurological evaluations, extensive cognitive testing, and imaging, impose undesirable costs and delays, and are largely impractical to implement on a battlefield. Thus, the military has a significant need to make fast and accurate neurocognitive assessments of its personnel.
Currently available screening procedures for mTBI are largely based on a use of standard questionnaires or self-reporting of the trauma or symptoms. Standard questionnaires can be administered by emergency personnel. Some example questionnaires include the Military Acute Concussion Evaluation (MACE), the Westmead Post Traumatic Amnesia Scale (PTA), and the Acute Concussion Evaluation (ACE). However, these evaluation methods are often unreliable and impractical to administer immediately after injury in the field. For example, MACE is primarily designed to be most effective when administered immediately after injury, and studies suggest that it is clinically useful within 6 hours but ineffective after 12 hours. However, administering a dense questionnaire in the battlefield immediately following a traumatic exposure is not always practical. Recently, a number of other tests have been developed to diagnose mTBI, including the Automated Neuropsychological Assessment Test (ANAM), the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), and the King-Devick (K-D) Test. Despite these advances, however, screening and diagnosis of mTBI still largely depend on standard questionnaires and clinical observation. There is currently no gold standard or objective means to screen for and diagnose mTBI.
As disclosed in WO 2014/039861, the content of which is hereby incorporated by reference in its entirety, it is possible to measure and monitor an individual's motor performance variability immediately after injury in the field. More specifically, WO 2014/039861 discloses a method and system for assessing intra-individual response variability as manifested in a simple motor task to screen for mTBI and to potentially diagnose mTBI or other cognitive impairments.
However, the system disclosed in WO 2014/039861 fails to achieve a high degree of accuracy for its diagnosis. It implements a simple binary classifier and simple metrics that cannot diagnose mTBI with a sufficient degree of accuracy to make its use practical as a reliable mTBI screening system. Thus, the system disclosed in WO 2014/039861 alone does not negate the need for additional testing of the subject to ensure a reliable diagnosis. Therefore, it would be helpful to rapidly screen for mTBI with a high degree of accuracy to allow for its easy and reliable use in a real world setting.